dmucs: command not found

Maybe Your $PATH variable doesn't contain the default paths? echo $PATH should give something like:

[root@server ~]# echo $PATH
/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin

If it's empty, You may set the PATH variable with this command

export PATH="/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin"

On Debian possible default full paths are:

/usr/sbin/dmucs - from package: dmucs

You may install the required package with command apt-get install {package}

Error in other languages:
dmucs: bevel nie gevind nie
dmucs: comandă negăsită
dmucs: comando não encontrado
dmucs: commande introuvable
dmucs: command not found
dmucs: käsku ei ole
dmucs: không tìm thấy lệnh
dmucs: komanda nerasta
dmucs: Kommando nicht gefunden.
dmucs: kommandot finns inte
dmucs: komut yok
dmucs: nie znaleziono polecenia
dmucs: níor aimsíodh an t-ordú
dmucs: no se encontró la orden
dmucs: no s'ha trobat l'ordre
dmucs: opdracht niet gevonden
dmucs: parancs nem található
dmucs: perintah tidak ditemukan
dmucs: príkaz nenájdený
dmucs: příkaz nenalezen
dmucs: команда не найдена
dmucs: командата не е открита
dmucs: 命令找不到
dmucs: コマンドが見つかりません